It's a pretty cool vid. You may think that there are way too many does in the video, but I believe what we watched are deer yarded up around a major winter food source. Deer during harsh times in the northern states will flock from miles. Sometimes ten or more.
I saw it last month in WI where the deer numbers in the northern portion of the state are low. There was a 200 acre corn field still standing and there must have been 300 deer standing in it feeding at 1200 pm. It was quite a sight.
Once the weather lets up the deer start to spread out again.